When \(\operatorname{div}_x\mathbf {c}\ne 0\) , the situation is more complicated, even when coefficients are in \(L^\infty \) . We define an \(n\) -dimensional divergence form operator \(L_{||}:= \operatorname{div}A_{||}\nabla \) , and its adjoint \(L^*_{||}:=-\operatorname{div}A^*_{||}\nabla \) . We highlight three ingredients in the proof of the \(A_{\infty }\)  condition for elliptic measure associated to operators with \(L^{\infty }\) , \(t\) -independent coefficients in [1]}:
